Semiconductor package

ABSTRACT

A semiconductor package includes: a first semiconductor chip in which a through-electrode is provided; a second semiconductor chip connected to a top surface of the first semiconductor chip; a first connection bump attached to a bottom surface of the first semiconductor chip and including a first pillar structure and a first solder layer; and a second connection bump located between the first semiconductor chip and the second semiconductor chip, configured to electrically connect the first semiconductor chip and the second semiconductor chip, and including a second pillar structure and a second solder layer.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2016-0060362, filed on May 17, 2016, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

The inventive concept relates to a semiconductor package, and moreparticularly, to a semiconductor package including a through-substratevia (TSV) structure.

As the electronic industry has grown rapidly and user demands haveincreased, electronic devices have become smaller and lighter.Accordingly, smaller and lighter semiconductor packages having highperformance and a large storage capacity are needed in electronicdevices. For semiconductor packages to be small and light and to havehigh performance and a large storage capacity, semiconductor chips thathave a TSV structure and semiconductor packages that include the suchsemiconductor chips are needed.

SUMMARY

The inventive concept provides a semiconductor package that is small andlight and has high performance and large storage capacity and a methodof manufacturing the semiconductor package.

According to an aspect of the inventive concept, there is provided asemiconductor package including: a first semiconductor chip in which athrough-electrode is provided; a second semiconductor chip connected toa top surface of the first semiconductor chip; a first connection bumpattached to a bottom surface of the first semiconductor chip andincluding a first pillar structure and a first solder layer; and asecond connection bump located between the first semiconductor chip andthe second semiconductor chip, configured to electrically connect thefirst semiconductor chip and the second semiconductor chip, andincluding a second pillar structure and a second solder layer, whereinthe first pillar structure includes a material that is different from amaterial of the second pillar structure.

According to another aspect of the inventive concept, there is provideda semiconductor package including: a substrate; a first semiconductorchip mounted on a top surface of the substrate and including athrough-electrode provided therein; a second semiconductor chip mountedon a top surface of the first semiconductor chip; a first connectionbump located between the first semiconductor chip and the substrate andincluding a first pillar structure and a first solder layer; and asecond connection bump located between the first semiconductor chip andthe second semiconductor chip and including a second pillar structureand a second solder layer, wherein the first pillar structure includes amaterial that is different from a material of the second pillarstructure.

According to another aspect of the inventive concept, there is provideda semiconductor package including: a substrate; at least twosemiconductor chips mounted on a top surface of the substrate andstacked in a first direction that is perpendicular to the top surface ofthe substrate; an inter-chips connection bump located between the atleast two semiconductor chips and configured to electrically connect twoadjacent semiconductor chips from among the at least two semiconductorchips; a chip-substrate connection bump located between the substrateand a semiconductor chip that is the closest to the substrate from amongthe at least two semiconductor chips and having a stacked structure thatis different from a stacked structure of the inter-chips connectionbump; and an external connection terminal mounted on a bottom surface ofthe substrate, wherein a width of the external connection terminal in asecond direction that is parallel to the top surface of the substrate isgreater than a width of the inter-chips connection bump or thechip-substrate connection bump.

According to an aspect of the inventive concept, a method to form asemiconductor package comprises: forming a through-electrode through asemiconductor substrate; forming a first connection pad on a firstsurface of the through-electrode; forming a first connection bump on thefirst connection pad, the first connection bump having a first pillarstructure that comprises a first material having a first Young'smodulus; forming a first upper connection pad on a second surface of thethrough-electrode, the second surface opposite to the first surface;forming a second connection bump on the first upper connection pad, thesecond connection bump having a second pillar structure that comprises asecond material, wherein the first material that is different from thesecond material.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the inventive concept will be more clearly understoodfrom the following detailed description taken in conjunction with theaccompanying drawings in which:

FIG. 1A is a plan view of a semiconductor package according to someembodiments;

FIG. 1B is a cross-sectional view taken along line 1B-1B′ of FIG. 1A;

FIG. 1C is an enlarged view illustrating a portion 1C of FIG. 1B;

FIG. 1D is an enlarged view illustrating a portion 1D of FIG. 1B:

FIG. 2 is a cross-sectional view of a semiconductor package according tosome embodiments;

FIG. 3 is a cross-sectional view of a semiconductor package according tosome embodiments;

FIG. 4 is a cross-sectional view of a semiconductor package according tosome embodiments;

FIG. 5 is a cross-sectional view of a semiconductor package according tosome embodiments;

FIG. 6 is a cross-sectional view of a semiconductor package according tosome embodiments;

FIG. 7 is a cross-sectional view of a semiconductor package according tosome embodiments;

FIG. 8 is a cross-sectional view of a semiconductor package according tosome embodiments;

FIG. 9 is a cross-sectional view of a semiconductor package according tosome embodiments;

FIG. 10 is a cross-sectional view of a semiconductor package accordingto some embodiments; and

FIGS. 11 through 21 are cross-sectional views for explaining a method ofmanufacturing a semiconductor package according to a process orderaccording to some embodiments.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The inventive concept will now be described more fully regarding theaccompanying drawings, in which some embodiments of the inventiveconcept are shown.

FIG. 1A is a plan view of a semiconductor package 1 according to someembodiments. FIG. 1B is a cross-sectional view taken along line 1B-1B′of FIG. 1A. FIG. 1C is an enlarged view illustrating a portion 1C ofFIG. 1B. FIG. 1D is an enlarged view illustrating a portion 1D of FIG.1B.

Referring to FIGS. 1A through 1D, the semiconductor package 1 mayinclude a first semiconductor chip C1, a second semiconductor chip C2, athird semiconductor chip C3, and a fourth semiconductor chip C4 that arestacked in a first direction (e.g., a vertical direction, a Z-directionof FIG. 1B).

The semiconductor package 1 may include a cell region CR and a padregion PR. The pad region PR may be a region where first through thirdthrough-electrodes 120, 220, and 320, first through fourth connectionpads 132, 232, 332, and 432, and first through fourth connection bumps140, 240, 340, and 440 for electrically connecting the first throughfourth semiconductor chips C1, C2, C3, and C4 are formed. FIG. 1Aillustrates a bottom surface of the semiconductor package 1, that is, abottom surface of the first semiconductor chip C1 through which thefirst connection pad 132 and the first connection bump 140 are exposed.

A plurality of the first connection pads 132 may be arranged in any ofvarious layouts in an X-direction and a Y-direction in the pad regionPR. For example, as shown in FIG. 1A, the first connection pads 132 maybe arranged in a matrix with a predetermined pitch in the X-directionand the Y-direction in the pad region PR. For example, each of the firstconnection pads 132 may have a square shape, and a length of each sideof the square shape may range from about 20 μm to about 40 μm. However,a shape and an arrangement of the first connection pads 132 are notlimited thereto. Also, although six first connection pads 132 arearranged in the X-direction in the pad region PR and two firstconnection pads 132 are arranged in the Y-direction in the pad region PRfor convenience of explanation, the number of the first connection pads132 is not limited to that shown in FIG. 1A. Additionally, although thepad region PR is depicted in FIG. 1A as being located generally in acentral region of the semiconductor package 1, it should be understoodthat the pad region PR may be located along a periphery edge of thesemiconductor package 1. Moreover, it should be understood that thesemiconductor package 1 may have multiple pad regions PR.

The first through fourth semiconductor chips C1, C2, C3, and C4 may be,for example, memory semiconductor chips. The memory semiconductor chipsmay be volatile memory semiconductor chips such as dynamic random-accessmemories (DRAMs) or static random-access memories (SRAMs) ornon-volatile memory semiconductor chips such as phase-changerandom-access memories (PRAMs), magnetoresistive random-access memories(MRAMs), ferroelectric random-access memories (FeRAMs), or resistiverandom-access memories (RRAMs). In an embodiment, the first throughfourth semiconductor chips C1, C2, C3, and C4 may be high-bandwidthmemory (HBM) DRAMs.

Although the semiconductor package 1 in which the first through fourthsemiconductor chips C1, C2, C3, and C4 are stacked is illustrated inFIGS. 1A through 1D, the number of semiconductor chips stacked in thesemiconductor package 1 is not limited thereto. For example, 2 through32 semiconductor chips may be stacked in the semiconductor package 1.

The first connection bump 140 may be disposed on the bottom surface ofthe first semiconductor chip C1. The second semiconductor chip C2 may bemounted on a top surface of the first semiconductor chip C1, and thesecond connection bump 240 may be disposed between the secondsemiconductor chip C2 and the first semiconductor chip C1 and mayelectrically connect the second semiconductor chip C2 and the firstsemiconductor chip C1. The third semiconductor chip C3 may be mounted onthe second semiconductor chip C2 and may be electrically connected tothe second semiconductor chip C2 by the third connection bump 340. Also,the fourth semiconductor chip C4 may be mounted on the thirdsemiconductor chip C3 and may be electrically connected to the thirdsemiconductor chip C3 by the fourth connection bump 440. The firstconnection bump 140 may have a structure that is different from those ofthe second through fourth connection bumps 240, 340, and 440. In someembodiments, the second through fourth connection bumps 240, 340, and440 may have substantially the same structure.

The first semiconductor chip C1 may include a first semiconductorsubstrate 100, a first semiconductor device layer 110, the firstthrough-electrode 120, and the first connection pad 132. As shown inFIG. 1C, the first semiconductor substrate 100 may have a top surface102 and a bottom surface 104 that are opposite to each other, and thefirst semiconductor device layer 110 may be formed on the bottom surface104 of the first semiconductor substrate 100. The firstthrough-electrode 120 may pass through the first semiconductor substrate100, may extend from the top surface 102 to the bottom surface 104 ofthe first semiconductor substrate 100, and may extend into the firstsemiconductor device layer 110. The first connection pad 132 may beformed on the bottom surface 104 of the first semiconductor substrate100 with the first semiconductor device layer 110 therebetween and maybe electrically connected to the first through-electrode 120.

For convenience of explanation, a surface of the first semiconductorsubstrate 100 that is close to the second semiconductor chip C2 isreferred to as the top surface 102 and a surface of the firstsemiconductor substrate 100 that is close to the first connection bump140 is referred to as the bottom surface 104. However, the following maybe explained on the assumption that the semiconductor package 1 isreversed so that the top surface 102 of the first semiconductorsubstrate 100 faces downward and the bottom surface 104 of the firstsemiconductor substrate 100 faces upward. For example, the firstconnection pad 132 may be formed on the first semiconductor device layer110, and in this case, it may mean that the first semiconductor devicelayer 110 and the first connection pad 132 are sequentially formed in anorder in which the first semiconductor device layer 110 and the firstconnection pad 132 are positioned distally from the bottom surface 104of the first semiconductor substrate 100.

The first semiconductor substrate 100 may include, for example, silicon(Si). Alternatively, the first semiconductor substrate 100 may include asemiconductor element such as germanium (Ge) or a compound semiconductorsuch as silicon carbide (SiC), gallium arsenide (GaAs), indium arsenide(InAs), or indium phosphide (InP). Alternatively, the firstsemiconductor substrate 100 may have a silicon-on-insulator (SOI)structure. For example, the first semiconductor substrate 100 mayinclude a buried oxide (BOX) layer. The first semiconductor substrate100 may include a conductive region, for example, a well doped withimpurities or a structure doped with impurities. Also, the firstsemiconductor substrate 100 may have any of various device isolationstructures such as a shallow trench isolation (STI) structure.

The first semiconductor device layer 110 may include a variety ofindividual devices and an insulating interlayer (not shown). Theplurality of individual devices may include various microelectronicdevices, for example, a metal-oxide-semiconductor field effecttransistor (MOSFET) such as a complementarymetal-insulator-semiconductor (CMOS) transistor, a large scaleintegration (LSI) system, a flash memory, a DRAM, an SRAM, anelectrically erasable programmable read-only memory (EEPROM), a PRAM, anMRAM, or an RRAM, an image sensor such as a CMOS imaging sensor (CIS), amicro-electro-mechanical system (MEMS), an active device, and a passivedevice. The plurality of individual devices may be formed in the firstsemiconductor device layer 110 in the cell region CR, and may beelectrically connected to the conductive region of the firstsemiconductor substrate 100. The first semiconductor device layer 110may further include a conductive wiring line or a conductive plug forelectrically connecting at least two of the plurality of individualdevices or the plurality of individual devices and the conductive regionof the first semiconductor substrate 100. Also, the plurality ofindividual devices may be electrically isolated from other adjacentindividual devices by insulating films.

The first semiconductor device layer 110 may include a plurality ofwiring structures 112 for connecting the plurality of individual devicesand other wiring lines formed in the first semiconductor substrate 100.Each of the plurality of wiring structures may include a conductivewiring layer such as a metal wiring layer 114 and a via plug 116. Themetal wiring layer 114 and the via plug 116 may include a wiring barrierfilm and a wiring metal layer. The wiring barrier film may include atleast one material selected from among titanium (Ti), titanium nitride(TiN), tantalum (Ta), and tantalum nitride (TaN). The wiring metal layermay include at least one metal selected from among tungsten (W),aluminium (Al), and copper (Cu). The metal wiring layer 114 and the viaplug 116 may be formed of the same material. Alternatively, at leastportions of the metal wiring layer 114 and the via plug 116 may includedifferent materials. A plurality of the metal wiring layers 114 and/orthe via plugs 116 may be stacked. That is, the plurality of wiringstructures 112 may be multi-layer structures in which two or more metalwiring layers 114 or two or more via plugs 116 are alternately stacked.

The first through-electrode 120 may extend from the top surface 102 tothe bottom surface 104 of the first semiconductor substrate 100 and mayextend into the first semiconductor device layer 110. At least a portionof the first through-electrode 120 may have a pillar shape. The firstthrough-electrode 120 may include a barrier film 122 that is formed on asurface of the pillar shape and a buried conductive layer 124 that isfilled in the barrier film 122. The barrier film 122 may include atleast one material selected from among Ti, TiN, Ta, TaN, ruthenium (Ru),cobalt (Co), manganese (Mn), tungsten nitride (WN), nickel (Ni), andnickel boride (NiB), and the buried conductive layer 124 may include atleast one material selected from among Cu, a Cu alloy such as copper-tin(CuSn), copper-magnesium (CuMg), copper-nickel (CuNi), copper-zinc(CuZn), copper-palladium (CuPd), copper-gold (CuAu), copper-rhenium(CuRe), or copper-tungsten (CuW), tungsten (W), a W alloy, Ni, Ru, andCo. A via insulating film 126 may be disposed between the firstsemiconductor substrate 100 and the first through-electrode 120 andbetween the first semiconductor device layer 110 and the firstthrough-electrode 120. The via insulating film 126 may include an oxidefilm, a nitride film, a carbide film, a polymer, or a combinationthereof.

The first connection pad 132 may be disposed on the first semiconductordevice layer 110 and may be electrically connected to the plurality ofwiring structures 112 in the first semiconductor device layer 110. Thefirst connection pad 132 may be electrically connected to the firstthrough-electrode 120 through the plurality of wiring lines 112. Thefirst connection pad 132 may include at least one of Al, Cu, Ni, W,platinum (Pt), or gold (Au).

A first passivation layer 130 that covers at least a portion of a topsurface of the first connection pad 132 may be formed on the firstsemiconductor device layer 110. The first passivation layer 130 may be aprotective layer for protecting the plurality of wiring structures 112in the first semiconductor device layer 110 and other structures underthe plurality of wiring structures 112 from an external impact ormoisture. For example, the first passivation layer 130 may include aninorganic insulating film or an organic insulating film. In anembodiment, the first passivation layer 130 may be formed of siliconnitride. A hole 130H through which at least a portion of the top surfaceof the first connection pad 132 is exposed may be formed in the firstpassivation layer 130.

A first rear protective layer 136 may be formed on the top surface 102of the first semiconductor substrate 100 to surround the firstthrough-electrode 120. A first upper connection pad 134 that iselectrically connected to the first through-electrode 120 may be formedon the first rear protective layer 136, overlying the top surface 102 ofthe first semiconductor substrate 100. The first upper connection pad134 may include at least one of Al, Cu, Ni, W, Pt, or Au.

The first connection bump 140 may be disposed on the exposed portion ofthe first connection pad 132 and on a portion of the first passivationlayer 130. The first connection bump 140 may be disposed on a lowermostsurface of the semiconductor package 1. The first connection bump 140may be a chip-substrate connection bump for mounting the semiconductorpackage 1 on an external substrate (not shown) or an interposer (notshown). The first connection bump 140 may receive at least one of acontrol signal, a power signal, or a ground signal for operating thefirst through fourth semiconductor chips C1, C2, C3, and C4 from theoutside, may receive a data signal to be stored in the first throughfourth semiconductor chips C1, C2, C3, and C4 from the outside, or maytransmit data stored in the first through fourth semiconductor chips C1,C2, C3, and C4 to the outside.

The first connection bump 140 may include a first pillar structure 142and a first solder layer 148. The first pillar structure 142 may includea first pillar layer 144 that is connected to the first connection pad132 and a diffusion barrier layer 146 that is disposed on the firstpillar layer 144. Therefore, the first connection bump 140 may have thefirst pillar layer 144 and the first solder layer 148 with the diffusionbarrier layer 146 disposed therebetween.

In some embodiments, the first pillar layer 144 may include Ni, Cu,palladium (Pd), Pt, Au, or a combination thereof. For example, the firstpillar layer 144 may include a material having a relatively low Young'smodulus. For example, the first pillar layer 144 may include a materialhaving a Young's modulus ranging from about 100 GPa to about 180 GPa. Insome embodiments, the first pillar layer 144 may include, but notlimited to, Cu or a Cu alloy. A material of the first pillar layer 144will be described below in greater detail.

In some embodiments, the diffusion barrier layer 146 may include Ni, Co,Cu, or a combination thereof. The diffusion barrier layer 146 mayinclude a material that is different from that of the first pillar layer144. For example, when the first pillar layer 144 includes Cu, thediffusion barrier layer 146 may include Ni or a Ni alloy. The diffusionbarrier layer 146 may prevent an excessive amount of intermetalliccompounds from being formed due to a reaction between the first solderlayer 148 and the first pillar layer 144, thereby preventing a void frombeing formed in the first solder layer 148.

Although not shown, an under bump metal (UBM) layer (not shown) may befurther formed between the first pillar structure 142 and the firstconnection pad 132. The UBM layer may be a seed layer, an adhesivelayer, or a barrier layer for forming the first pillar structure 142.For example, the UBM layer may include chromium (Cr), W, Ti, Cu, Ni, Al,Pd, Au, or a combination thereof.

The UBM layer may be a single layer of metal or may have a stackedstructure including a plurality of metal layers. For example, the UBMlayer may include a first metal layer, a second metal layer, and/or athird metal layer that are sequentially stacked on the first connectionpad 132. The first metal layer may act as an adhesive layer for stablyattaching the first connection bump 140 to the first connection pad 132and/or the first passivation layer 130. The first metal layer mayinclude a metal material having excellent adhesion properties to thefirst passivation layer 130. For example, the first metal layer mayinclude at least one of Ti, Ti—W, Cr, or Al. The second metal layer mayact as a barrier layer for preventing a metal material included in thefirst connection pad 132 from diffusing into the first semiconductorsubstrate 100. The second metal layer may include at least one of Cu,Ni, Cr—Cu, or Ni-vanadium (V). The third metal layer may act as awetting layer for improving wetting properties of a seed layer or asolder layer for forming the first connection bump 140. The third metallayer may include at least one of Ni, Cu, or Al.

The first solder layer 148 may be disposed on the diffusion barrierlayer 146. In some embodiments, the first solder layer 148 may have aspherical shape or a ball shape. The first solder layer 148 may includetin (Sn), indium (In), bismuth (Bi), antimony (Sb), Cu, silver (Ag),zinc (Zn), lead (Pb), and/or an alloy thereof. For example, the firstsolder layer 148 may include Sn, Pb, Sn—Pb, Sn—Ag, Sn—Au, Sn—Cu, Sn—Bi,Sn—Zn, Sn—Ag—Cu, Sn—Ag—Bi, Sn—Ag—Zn, Sn—Cu—Bi, Sn—Cu—Zn, Sn—Bi—Zn orcombinations thereof.

An intermediate layer (not shown) may be formed on a contact interfacebetween the first solder layer 148 and the first pillar structure 142.The intermediate layer may include an intermetallic compound (IMC) thatis formed due to a reaction between metal materials included in thesolder layer 148 and the first pillar structure 142 at a relatively hightemperature. For example, when the first pillar structure 142 includesCu and/or Ni and the first solder layer 148 includes Sn and/or Cu, theintermediate layer may be formed to include at least one of (Cu,Ni)₆Sn₅,(Cu,Ni)₃Sn₄, or (Cu,Ni)₃Sn. A material or a combination of theintermediate layer is not, however, limited thereto, and may vary basedon a material of the first pillar structure 142, a material of the firstsolder layer 148, and a temperature and a time of a reflow process.

As shown in FIG. 1B, the second semiconductor chip C2 may be mounted onthe top surface of the first semiconductor chip C1, and the secondconnection bump 240 may be disposed between the first semiconductor chipC1 and the second semiconductor chip C2 to electrically connect thesecond semiconductor chip C2 and the first semiconductor chip C1. Thesecond semiconductor chip C2 may include a second semiconductorsubstrate 200, a second semiconductor device layer 210, the secondthrough-electrode 220, and the second connection pad 232.

As shown in FIG. 1D, a second passivation layer 230 is formed to cover aportion of a top surface of the second connection pad 232 and on thesecond semiconductor device layer 210. The second semiconductor chip C2and the first semiconductor chip C1 have similar technicalcharacteristics, and thus a detailed explanation of the secondsemiconductor chip C2 will be omitted.

Referring back to FIG. 1B, the second connection bump 240 may bedisposed between the second connection pad 232 and the first upperconnection pad 134 and may electrically connect the first semiconductorchip C1 and the second semiconductor chip C2. As shown in FIG. 1B, thesecond connection bump 240 may include a second pillar structure 242 anda second solder layer 248.

The second pillar structure 242 may be formed on the second connectionpad 232 and the second passivation layer 230 and may be electricallyconnected to the second through-electrode 220. In some embodiments, thesecond pillar structure 242 may include a material that is differentfrom a material included in the first pillar layer 144 of the firstpillar structure 142. For example, the second pillar structure 242 mayinclude a material having better high-temperature properties than amaterial included in the first pillar layer 144. In particular, sincethe second pillar structure 242 includes a material having betterhigh-temperature properties than a material included in the first pillarlayer 144, a void, which occurs due to a reaction between the secondsolder layer 248 and the second pillar structure 242 at a hightemperature, may be prevented from being formed in the second solderlayer 248. In some embodiments, the second pillar structure 242 mayinclude Ni, Cu, Pd, Pt, Au, or a combination thereof. For example, thesecond pillar structure 242 may include, but not limited to, Ni or a Nialloy.

The second solder layer 248 may be disposed between the second pillarstructure 242 and the first upper connection pad 134. The second solderlayer 248 may include Sn, In, Bi, Sb, Cu, Ag, Zn, Pb, and/or an alloythereof. For example, the second solder layer 248 may include Sn, Pb,Sn—Pb, Sn—Ag, Sn—Au, Sn—Cu, Sn—Bi, Sn—Zn, Sn—Ag—Cu, Sn—Ag—Bi, Sn—Ag—Zn,Sn—Cu—Bi, Sn—Cu—Zn, or Sn—Bi—Zn.

Although not shown, an intermediate layer (not shown) may be formed on acontact interface between the second solder layer 248 and the secondpillar structure 242 and/or a contact interface between the secondsolder layer 248 and the first upper connection pad 134. Theintermediate layer may include an intermetallic compound formed due to areaction between metal materials included in the second solder layer 248and the first upper connection pad 134 and/or metal materials includedin the second solder layer 248 and the second pillar structure 242.

The third semiconductor chip C3 may be mounted on a top surface of thesecond semiconductor chip C2 and the fourth semiconductor chip C4 may bemounted on a top surface of the third semiconductor chip C3. The thirdconnection bump 340 may be disposed between the second semiconductorchip C2 and the third semiconductor chip C3 and the fourth connectionbump 440 may be disposed between the third semiconductor chip C3 and thefourth semiconductor chip C4.

The third semiconductor chip C3 may include a third semiconductorsubstrate 300, a third semiconductor device layer 310, the thirdthrough-electrode 320, and the third connection pad 332. The fourthsemiconductor chip C4 may include a fourth semiconductor substrate 400,a fourth semiconductor device layer 410, and the fourth connection pad432. Since the third semiconductor chip C3 and the fourth semiconductorchip C4 may have technical characteristics similar to those of the firstsemiconductor chip C1, a detailed explanation of the third and fourthsemiconductor chips C3 and C4 will be omitted.

The third connection bump 340 may be disposed between the thirdconnection pad 332 and the second upper connection pad 234 and mayelectrically connect the second semiconductor chip C2 and the thirdsemiconductor chip C3. The third connection bump 340 may include a thirdpillar structure 342 and a third solder layer 348. The fourth connectionbump 440 may be disposed between the fourth connection pad 432 and thethird upper connection pad 334 and may electrically connect the thirdsemiconductor chip C3 and the fourth semiconductor chip C4. The fourthconnection bump 440 may include a fourth pillar structure 442 and afourth solder layer 448. Since the third connection bump 340 and thefourth connection bump 440 may have technical characteristics similar tothose of the second connection bump 240, a detailed explanation of thethird and fourth connection bumps 340 and 440 will be omitted. Thesecond through fourth connection bumps 240, 340, and 440 may beinter-chips connection bumps disposed between the first through fourthsemiconductor chips C1, C2, C3, and C4.

In some embodiments, a first molding member 150 may surround the topsurface of the first semiconductor chip C1 and side surfaces of thesecond through fourth semiconductor chips C2, C3, and C4. The firstmolding member 150 may include first through third insulating layers152, 154, and 156 and a first molding layer 162.

The first insulating layer 152 may be disposed between the top surfaceof the first semiconductor chip C1 and a bottom surface of the secondsemiconductor chip C2 and may surround side surfaces of the secondconnection bump 240. The second insulating layer 154 may be disposedbetween the top surface of the second semiconductor chip C2 and a bottomsurface of the third semiconductor chip C3 and may surround sidesurfaces of the third connection bump 340. The third insulating layer156 may be disposed between the top surface of the third semiconductorchip C3 and a bottom surface of the fourth semiconductor chip C4 and maysurround side surfaces of the fourth connection bump 440. As shown inFIG. 1B, side surfaces of the first through third insulating layers 152,154, and 156 may protrude outward by a predetermined width in theX-direction. However, the inventive concept is not limited thereto.

The first molding layer 162 may surround the side surfaces of the firstthrough third insulating layers 152, 154, and 156 and the side surfacesof the second through fourth semiconductor chips C2, C3, and C4. Asshown in FIG. 1A, a width of the first semiconductor chip C1 in ahorizontal direction (e.g., the X-direction) may be greater than widthsof the second through fourth semiconductor chips C2, C3, and C4 in thehorizontal direction, and the first molding layer 162 may contact anedge of a top surface of the first semiconductor chip C1. However, theinventive concept is not limited thereto. Also, the first molding layer162 may be formed on a portion of a top surface of the fourthsemiconductor chip C4 to a predetermined thickness. In some otherembodiments, for example, the first molding layer 162 may not be formedon the top surface of the fourth semiconductor chip C4 and the topsurface of the fourth semiconductor chip C4 may be exposed to theoutside of the semiconductor package 1 in contrast to FIG. 1B.

In some embodiments, each of the first through third insulating layers152, 154, and 156 may include an underfill material such as aninsulating polymer or epoxy resin. The first molding layer 162 mayinclude an epoxy mold compound (EMC).

In some embodiments, the first molding member 150 may surround the topsurface of the first semiconductor chip C1 and the side surfaces of thesecond through fourth semiconductor chips C2, C3, and C4, and mayinclude a single material layer. That is, the first molding member 150may be disposed between the first through fourth semiconductor chips C1,C2, C3, and C4, and may surround the side surfaces of the second throughfourth semiconductor chips C2, C3, and C4 and may surround the sidesurfaces of the second through fourth connection bumps 240, 340, and440. In this case, since the first molding member 150 is not formed onthe bottom surface of the first semiconductor chip C1, the first moldingmember 150 and the first connection bump 140 may not directly contacteach other. In some embodiments, the first molding member 150 mayinclude a material that is formed by using a molded underfill (MUF)method.

As shown in FIG. 1C, the first pillar structure 142 of the firstconnection bump 140 may have a first height HP1 in a vertical direction(e.g., the Z-direction). The first height HP1 of the first pillarstructure 142 refers to a distance between an uppermost surface of thefirst pillar layer 144 that contacts the first connection pad 132 and alowermost surface of the diffusion barrier layer 146 that contacts thefirst solder layer 148 in the Z-direction. The first height HP1 of thefirst pillar structure 142 may range from about 10 μm to about 30 μm.Also, the first solder layer 148 may have a second height HS1 in avertical direction, and the second height HS1 of the first solder layer148 may range, for example, from about 5 μm to about 30 μm. However, thefirst height HP1 of the first pillar structure 142 and the second heightHS1 of the first solder layer 148 are not limited thereto.

As shown in FIG. 1D, the second pillar structure 242 of the secondconnection bump 240 may have a third height HP2 in a vertical direction(e.g., the Z-direction). The third height HP2 of the second pillarstructure 242 refers to a distance between an uppermost surface of thesecond pillar structure 242 that contacts the second connection pad 232and a lowermost surface of the second pillar structure 242 that contactsthe second solder layer 248. The third height HP2 of the second pillarstructure 242 may range from about 2 μm to about 10 μm. Also, the secondsolder layer 248 may have a fourth height HS2 in a vertical direction,and the fourth height HS2 of the second solder layer 248 may range, forexample, from about 5 μm to about 20 μm. However, the third height HP2of the second pillar structure 242 and the fourth height HS2 of thesecond solder layer 248 are not limited thereto.

The first height HP1 of the first pillar structure 142 of the firstconnection bump 140 may be greater than the third height HP2 of thesecond pillar structure 242 of the second connection bump 240. Also, thesecond height HS1 of the first solder layer 148 of the first connectionbump 140 may be greater than the fourth height HS2 of the second solderlayer 248 of the second connection bump 240. Accordingly, a height H1(i.e., a sum of the first height HP1 and the second height HS1) of thefirst connection bump 140 in the Z-direction may be greater than aheight H2 (i.e., a sum of the third height HP2 and the fourth heightHS2) of the second connection bump 240 in the Z-direction.

In general, when a height of the connection bump 240 is too small, itmay be difficult to perform an underfill process for filling a spacebetween the connection bump 240 and the first and second semiconductorchips C1 and C2 or a space between the semiconductor chip C1 and anunderlying substrate (not shown). When heights of the first and secondconnection bumps 140 and 240 are too large, a total thickness of thesemiconductor package 1 may be increased and thus it may be difficult toobtain the semiconductor package 1 having a compact size. However,according to the semiconductor package 1 of the inventive concept, thefirst connection bump 140 that is a substrate-chip connection bump andthe second connection bump 240 that is an inter-chips connection bumpmay have different structures and the height H1 of the first connectionbump 140 may be greater than the height H2 of the second connection bump240. Accordingly, a sufficient underfill interval may be ensured betweenthe semiconductor package 1 and the substrate to be mounted under thesemiconductor package 1, while the semiconductor package 1 having acompact size may be obtained.

Also, since the height H1 of the first connection bump 140 is greaterthan the height H2 of the second connection bump 240, even when warpageoccurs in an underlying substrate (not shown) or an interposer (notshown), the first semiconductor package 1 may be stably adhered to thelower substrate or the interposer through the first connection bump 140.

Also, the first connection bump 140 and the second connection bump 240may have different structures and may include different materials. Indetail, the first pillar layer 144 of the first connection bump 140 mayinclude a material having a Young's modulus that is lower than that of amaterial included in the second pillar structure 242. For example, aYoung's modulus of Cu may range from about 110 GPa to about 128 GPa anda Young's modulus of Ni may be about 200 GPa. The first pillar layer 144may include Cu or a Cu alloy and the second pillar structure 242 mayinclude Ni or a Ni alloy. That is, when the first pillar layer 144includes a material having a Young's modulus that is lower than that ofa material included in the second pillar structure 242, the first pillarlayer 144 may have a relatively large elasticity responding to anexternal force or a pressure. Accordingly, even when a warpage occurs inan underlying substrate (not shown) or an interposer (not shown), sincethe first pillar layer 144 has a relatively large elasticity, a crackmay be prevented from being formed in an interface between the firstpillar layer 144 and the first solder layer 148.

Also, the second pillar structure 242 of the second connection bump 240may include a material having better high-temperature properties than amaterial included in the first pillar layer 144 of the first connectionbump 140. In general, when a semiconductor package in which a pluralityof semiconductor chips are stacked is manufactured, an inter-chipsconnection bump for connecting the plurality of semiconductor chips maybe exposed to multiple high-temperature processes. Accordingly, whenhigh-temperature properties of a material included in the inter-chipsconnection bump are poor, a large amount of intermetallic compounds maybe formed on a contact interface between a connection pad and a solderlayer due to the multiple high-temperature processes. Once the largeamount of intermetallic compounds are formed, the amount of soldersincluded in the solder layer may be reduced and a void may be formed inthe solder layer, thereby reducing the mechanical strength of aconnection bump or the reliability of the semiconductor package.However, according to the semiconductor package 1, since the secondthrough fourth connection bumps 240, 340, and 440 corresponding tointer-chips connection bumps may include a material having betterhigh-temperature properties than a material included in the firstconnection bump 140, an excessive amount of intermetallic compounds maybe prevented from being formed in a process of manufacturing thesemiconductor package 1 in which the plurality of semiconductor chipsC1, C2, C3, and C4 are stacked. Accordingly, the semiconductor package 1including the second through fourth connection bumps 240, 340, and 440may have a high mechanical strength and high reliability.

In conclusion, the first connection bump 140 includes a material havinga Young's modulus that is lower than that of a material included in thesecond connection bump 240 and the second connection bump 240 includes amaterial having better high-temperature properties than a materialincluded in the first connection bump 140. Accordingly, a crack may beprevented from being formed in the first connection bump 140 even when awarpage occurs during a process of mounting the first through fourthsemiconductor chips C1, C2, C3, and C4 on a substrate, and a void may beprevented from being formed in the second connection bump 240 even whenmultiple high-temperature processes for stacking the plurality ofsemiconductor chips C1, C2, C3, and C4 are performed. The semiconductorpackage 1 may have high adhesion reliability.

FIG. 2 is a cross-sectional view of a semiconductor package 1 aaccording to some embodiments. FIG. 2 is an enlarged view illustratingthe portion 1C of FIG. 1B. In FIG. 2, the reference numerals that arethe same as the reference numerals in FIGS. 1A through 1D denote thesame elements. The semiconductor package 1 a of FIG. 2 is similar to thesemiconductor package 1 of FIGS. 1A through 1D except for a first pillarstructure 142 a of a first connection bump 140 a, and thus the followingwill focus on the difference.

Referring to FIG. 2, the first connection bump 140 a may include thefirst pillar structure 142 a and the first solder layer 148, and thefirst pillar structure 142 a may include the first pillar layer 144, thediffusion barrier layer 146, and an adhesive layer 147, which aresequentially stacked.

The first pillar layer 144 may be disposed on a portion of the firstconnection pad 132 and on a portion of the first passivation layer 130,and may include a material having a Young's modulus that is lower thanthat of a material included in the second pillar structure 242. Forexample, the first pillar layer 144 may include Cu or a Cu alloy. Thediffusion barrier layer 146 may be formed on the first pillar layer 144and may include a material that is different from that of the firstpillar layer 144. For example, the diffusion barrier layer 146 mayinclude Ni or a Ni alloy. The adhesive layer 147 may be disposed on thediffusion barrier layer 146 and may contact the first solder layer 148.The adhesive layer 147 may be an intermediate layer for stably adheringthe first solder layer 148 and the first pillar structure 142. In someembodiments, the adhesive layer 147 may include Ni, Cu, Pd, Co, Pt, Au,or a combination thereof. For example, the adhesive layer 147 mayinclude, but not limited to, Cu or a Cu alloy. The adhesive layer 147may have a height ranging from, for example, about 2 μm to about 5 μm,in a vertical direction (e.g., the Z-direction). However, a height ofthe adhesive layer 147 may be appropriately selected according to acomposition of the first solder layer 148 and the second height HS1 ofthe first solder layer 148.

In some embodiments, the first pillar structure 142 a may have a firstheight HP1A ranging from about 10 μm to about 30 μm. The first solderlayer 148 may have the second height HS1 ranging from about 5 μm toabout 30 μm. Since the first pillar structure 142 a has a stackedstructure, in which the first pillar layer 144, the diffusion barrierlayer 146, and the adhesive layer 147 are sequentially stacked, thefirst height HP1A of the first pillar structure 142 a may be relativelylarge, for example, larger than the height of the first pillar structure142 of, for example, FIG. 1C. Accordingly, when the first connectionbump 140 a is mounted on an external substrate (not shown) or aninterposer (not shown), a relatively large interval, or space, may besecured between the semiconductor package 1 a and the external substrateor the interposer. A sufficient interval, or space, for forming anunderfill material layer may be secured between the semiconductorpackage 1 a and the external substrate or the interposer and sidesurfaces of the first connection bump 140 a may be surrounded by theunderfill material layer without a void.

Also, even when warpage occurs in the external substrate or theinterposer in a process for mounting the semiconductor package 1 a onthe external substrate or the interposer, the first semiconductorpackage 1 a and the external substrate or the interposer may be stablyadhered to each other due to a height H1A of the first connection bump140 a that is relatively large.

FIG. 3 is a cross-sectional view of a semiconductor package 1 baccording to some embodiments. FIG. 3 is an enlarged view illustrating aportion corresponding to the portion 1C of FIG. 1B. In FIG. 3, thereference numerals that are the same as the reference numerals in FIGS.1A through 2 denote the same elements. The semiconductor package 1 b ofFIG. 3 is similar to the semiconductor package 1 of FIGS. 1A through 1Cexcept for a structure of a first connection bump 140 b, and thus thefollowing will focus on the difference.

Referring to FIG. 3, the first connection bump 140 b may include a firstpillar structure 142 b and a first solder layer 148 b, and the firstpillar structure 142 b may include a first pillar layer 144 b, adiffusion barrier layer 146 b, and an adhesive layer 147 b, which aresequentially stacked.

The first pillar layer 144 b may have a first width WP1 in theX-direction and the diffusion barrier layer 146 b may have a secondwidth WB1 that is greater than the first width WP1 in the X-direction.For example, the first width WP1 of the first pillar layer 144 b mayrange from about 20 μm to about 40 μm and the second width WB1 of thediffusion barrier layer 146B may range from about 20 μm to about 45 μm.The first width WP1 of the first pillar layer 144 b may range from about80% to about 95% of the second width WB1 of the diffusion barrier layer146 b. The adhesive layer 147 b may have substantially the same width asthe first width WP1 of the first pillar layer 144 b in the X-direction.However, the inventive concept is not limited thereto. Unlike in FIG. 3,the adhesive layer 147 b may have substantially the same width as thesecond width WB1 of the diffusion barrier layer 146 b.

The first solder layer 148 b may contact a bottom surface and sidesurfaces of the adhesive layer 147 b and edge portions of a bottomsurface (i.e., a surface of the diffusion barrier layer 146 b thatcontacts the adhesive layer 147 b) of the diffusion barrier layer 146 bthat are not covered by the adhesive layer 147 b. The first solder layer148 b may have a second height HS1B in the Z-direction and the secondheight HS1B may range from about 5 μm to about 40 μm.

Since widths of the adhesive layer 147 b and the diffusion barrier layer146 b are different from each other, protrusions may be formed on sidesurfaces of the first pillar structure 142 b. Additionally, a contactarea between the adhesive layer 147 b and the diffusion barrier layer146 b and the first solder layer 148 b may be increased due to theprotrusions. As a contact area between the first solder layer 148 b andthe first pillar structure 142 b is increased, the amount or volume ofthe first solder layer 148 b that may be placed on the first pillarstructure 142 b without collapsing may be increased, and the secondheight HS1B of the first solder layer 148 b may also be increased.

Also, even when warpage occurs in a substrate or an interposer in aprocess for mounting the semiconductor package 1 b on the substrate orthe interposer, the semiconductor package 1 b and the substrate or theinterposer may be stably adhered to each other based on a height H1B ofthe first connection bump 140 b that is relatively large and/or arelative large volume of the first solder layer 148 b.

FIG. 4 is a cross-sectional view of a semiconductor package 1 caccording to some embodiments. FIG. 4 is an enlarged view illustrating aportion corresponding to the portion 1C of FIG. 1B. In FIG. 4, thereference numerals that are the same as the reference numerals in FIGS.1A through 3 denote the same elements. The semiconductor package 1 c ofFIG. 4 is similar to the semiconductor package 1 of FIGS. 1A through 1Dexcept for a structure of a first through-electrode 120 c, and thus thefollowing description focuses on the difference.

Referring to FIG. 4, in a process for manufacturing the firstsemiconductor chip C1 (see FIG. 1B), the first through-electrode 120 cmay be formed after a plurality of individual devices (not shown) andthe plurality of wiring structures 112 (see FIG. 1B) in the firstsemiconductor device layer 110 are formed. A portion of the firstsemiconductor device layer 110 including the plurality of individualdevices may be referred to as a front-end-of-line (FEOL) structure and aportion of the first semiconductor device layer 110 including theplurality of wiring structures 112 may be referred to as aback-end-of-line (BEOL) structure. That is, the first through-electrode120 c may be formed after the FEOL structure and the BEOL structure areformed. The first through-electrode 120 c may pass through the firstsemiconductor substrate 100 and the first semiconductor device layer110. The conductive barrier film 122 of the first through-electrode 120c may include a first outer wall portion that is surrounded by the firstsemiconductor substrate 100 and a second outer wall portion that issurrounded by the first semiconductor device layer 110.

The first connection pad 132 may be formed on the first semiconductordevice layer 110 to be located between the first through-electrode 120 cand the first connection bump 140, and the first through-electrode 120 cand the first connection bump 140 may be electrically connected to eachother through the first connection pad 132. In some embodiments, asshown in FIG. 4, the first through-electrode 120 c may directly contactthe first connection pad 132 without the wiring structures 112therebetween, which is unlike the embodiment shown in FIG. 2.

FIG. 5 is a cross-sectional view of a semiconductor package 1 daccording to some embodiments. FIG. 5 is an enlarged view correspondingto the portion 1C of FIG. 1B. In FIG. 5, the reference numerals that arethe same as the reference numerals in FIGS. 1A through 4 denote the sameelements. The semiconductor package 1 d of FIG. 5 is similar to thesemiconductor package 1 of FIGS. 1A through 1D except for a structure ofa first through-electrode 120 d, and thus the following will focus onthe difference.

Referring to FIG. 5, in a process for manufacturing the firstsemiconductor chip C1 (see FIG. 1B), after the first through-electrode120 d is formed, a plurality of individual devices (not shown) and theplurality of wiring structures 112 in the first semiconductor devicelayer 110 may be formed. That is, an FEOL structure and a BEOL structuremay be formed after the first through-electrode 120 d is formed.Accordingly, the first through-electrode 120 d passes through the firstsemiconductor substrate 100 and does not extend into the firstsemiconductor device layer 110. The first through-electrode 120 d may beconnected to the plurality of wiring structures 112 of the BEOLstructure through a conductive line 114 d and a contact plug 116 dincluded in the FEOL structure.

FIG. 6 is a cross-sectional view of a semiconductor package 1 eaccording to embodiments. FIG. 6 is a cross-sectional view taken alongline IB-1B′ of FIG. 1A. In FIG. 6, the reference numerals that are thesame as the reference numerals in FIGS. 1A through 5 denote the sameelements. The semiconductor package 1 e of FIG. 6 is similar to thesemiconductor package 1 of FIGS. 1A through 1D except for structures ofsecond through fourth connection bumps 240 e, 340 e, and 440 e, and thusthe following will focus on the difference.

Referring to FIG. 6, the second through fourth connection bumps 240 e,340 e, and 440 e may have structures that are different from that of thefirst connection bump 140. The first connection bump 140 may include thefirst pillar structure 142 and the first solder layer 148, and thesecond through fourth connection bumps 240 e, 340 e, and 440 e mayinclude the second through fourth pillar structures 242, 342, and 442and second through fourth solder layers 248 e, 348 e, and 448 e,respectively.

The first through fourth pillar structures 142, 242, 342, and 442 havesimilar technical characteristics to those described regarding FIGS. 1Athrough 1D, and thus a detailed explanation thereof will be omitted.

Each of the second through fourth solder layers 248 e, 348 e, and 448 emay include a material having a higher melting point than that of amaterial included in the first solder layer 148. For example, each ofthe second through fourth solder layers 248 e, 348 e, and 448 e mayinclude Sn, In, Bi, Sb, Cu, Ag, Zn, Pb, and/or an alloy thereof. Forexample, a melting point of a material included in each of the secondthrough fourth solder layers 248 e, 348 e, and 448 e may be, but notlimited to, higher by about 10° C. to about 200° C. than a melting pointof a material included in the first solder layer 148.

In general, when a semiconductor package, in which a plurality ofsemiconductor chips are stacked, is manufactured, an inter-chipsconnection bump for connecting the plurality of semiconductor chips maybe exposed to multiple high-temperature processes. Accordingly, when amelting point of a material included in the inter-chips connection bumpis relatively low, a large amount of intermetallic compounds may beformed on a contact interface between a connection pad and a solderlayer due to the plurality of high-temperature processes. Once the largeamount of intermetallic compounds are formed, the amount of soldersincluded in the solder layer may be reduced and a void may be formed inthe solder layer, thereby reducing the mechanical strength of aconnection bump or the reliability of the semiconductor package due tothe void.

However, according to the semiconductor package 1 e of the presentinventive concept, since each of the second through fourth solder layers248 e, 348 e, and 448 e corresponding to inter-chips connection bumpsmay include a material having a melting point that is higher than thatof a material included in the first solder layer 148, an excessiveamount of intermetallic compounds may be prevented from being formedduring a process of stacking the plurality of semiconductor chips C1,C2, C3, and C4. Accordingly, the semiconductor package 1 e including thesecond through fourth connection bumps 240 e, 340 e, and 440 e may havea high mechanical strength and high reliability.

FIG. 7 is a cross-sectional view of a semiconductor package 1 faccording to embodiments. FIG. 7 is a cross-sectional view taken alongline 1B-1B′ of FIG. 1A. In FIG. 7, the reference numerals that are thesame as the reference numerals in FIGS. 1A through 6 denote the sameelements. The semiconductor package 1 f of FIG. 7 is similar to thesemiconductor package 1 of FIGS. 1A through 1C except that a base die DOis further formed, and thus the following will focus on the difference.

Referring to FIG. 7, the base die DO may include a base substrate 500,an insulating interlayer 510, a base through-electrode 520, a baseconnection pad 532, and a base upper connection pad 534. The basethrough-electrode 520 may pass through the base substrate 500 from a topsurface to a bottom surface of the base substrate 500, and may extendinto the insulating interlayer 510. A plurality of wiring structures(not shown) may be formed in the insulating interlayer 510 and may beelectrically connected to the base through-electrode 520.

The first connection bump 140 may be mounted on a bottom surface of thebase die DO. In particular, the first connection bump 140 may bedisposed on the base connection pad 532 that is disposed on the bottomsurface of the base die DO. The technical features of the firstconnection bump 140 are similar to those described regarding FIGS. 1Athrough 1D.

The first through fourth semiconductor chips C1, C2, C3, and C4 may bestacked in a vertical direction (e.g., the Z-direction) on the topsurface of the base die DO. A fifth connection bump 240 a may bedisposed between the base upper connection pad 534 that is disposed onthe top surface of the base die DO and the first connection pad 132 thatis disposed on a bottom surface of the first semiconductor chip C1. Thefifth connection bump 240 a may include a fifth pillar structure 242 eand a fifth solder layer 248 a, and may have technical features that aresimilar to those of the second through fourth connection bumps 240, 340,and 440.

A fourth insulating layer 158 may be disposed between the base die DOand the first semiconductor chip C1, and may surround side surfaces ofthe fifth connection bump 240 a. The first molding layer 162 maysurround an outer wall of the fourth insulating layer 158.

The base die DO may be a dummy semiconductor chip that does not includeindividual devices included in the first through fourth semiconductorchips C1, C2, C3, and C4. The base die DO may be a buffer die that mayreceive at least one of a control signal, a power signal, or a groundsignal for operating the first through fourth semiconductor chips C1,C2, C3, and C4 through the base through-electrode 520 and the insulatinginterlayer 510 from the outside, may receive a data signal to be storedin the first through fourth semiconductor chips C1, C2, C3, and C4 fromthe outside, or may transmit data stored in the first through fourthsemiconductor chips C1, C2, C3, and C4 to the outside.

According to the semiconductor package 1 f, the first through fourthsemiconductor chips C1, C2, C3, and C4 may be stacked on the base die DOincluding the base through-electrode 520, which has the same structureas that of each of the first through fourth semiconductor chips C1, C2,C3, and C4. Accordingly, the second through fifth connection bumps 240,340, 440, and 240 a of the first through fourth semiconductor chips C1,C2, C3, and C4 are surrounded by the first molding member 150 and arenot exposed to the outside of the semiconductor package 1 f.Accordingly, undesired damage to the first through fourth semiconductorchips C1, C2, C3, and C4 may be avoided when the semiconductor package 1f is moved or stored.

Also, since each of the second through fifth connection bumps 240, 340,440, and 240 a that are inter-chips connection bumps includes a materialhaving excellent high-temperature properties, a void may be preventedfrom being formed during multiple high-temperature processes. Since thefirst connection bump 140 that is a substrate-chip connection bumpincludes a material having a low Young's modulus, even when warpageoccurs in a lower substrate or an interposer, excellent adhesionproperties may be ensured. Accordingly, the semiconductor package 1 fmay have high adhesion reliability.

FIG. 8 is a cross-sectional view of a semiconductor package 2 accordingto some embodiments. In FIG. 8, the reference numerals that are same asthe reference numerals in FIGS. 1A through 7 denote the same elements.The semiconductor package 2 of FIG. 8 is similar to the semiconductorpackage 1 of FIGS. 1A through 1D except that a package substrate 610 isadditionally formed, and thus the following will focus on thedifference.

Referring to FIG. 8, the semiconductor package 2 may include the firstthrough fourth semiconductor chips C1, C2, C3, and C4, which aresequentially stacked on the package substrate 610.

The first through fourth semiconductor chips C1, C2, C3, and C4 may beelectrically connected to one another through the corresponding firstthrough third through-electrodes 120, 220, and 320, and may beelectrically connected to the package substrate 610 through the firstthrough third through-electrodes 120, 220, and 320.

The package substrate 610 may be, for example, a printed circuit board(PCB), a ceramic substrate, or an interposer. When the package substrate610 is a PCB, the package substrate 610 may include a substrate base,and a top pad (not shown) and a bottom pad (not shown) that arerespectively formed on a top surface and a bottom surface of thesubstrate base. The top pad and the bottom pad may be exposed through asolder resist layer (not shown) that covers the top surface and thebottom surface of the substrate base. The substrate base may be formedof at least one material selected from among phenolic resin, epoxyresin, and polyimide. For example, the substrate base may include atleast one material selected from among FR4, tetrafunctional epoxy,polyphenylene ether, epoxy/polyphenylene oxide, bismaleimide triazine(BT), Thermount®, cyanate ester, polyimide, and liquid crystal polymer.Each of the top pad and the bottom pad may be formed of Cu, Ni,stainless steel, or beryllium copper. An internal wiring line (notshown) that electrically connects the top pad and the bottom pad may beformed in the substrate base. The top pad and the bottom pad may beobtained by applying a Cu foil to the top surface and the bottom surfaceof the substrate base and exposing portions of a patterned circuit linethrough the solder resist layer.

When the package substrate 610 is an interposer, the package substrate610 may include a substrate base formed of a semiconductor material anda top pad (not shown) and a bottom pad 612 that are respectively formedon a top surface and a bottom surface of the substrate base. Thesubstrate base may be formed from, for example, a silicon wafer. Also,an internal wiring line (not shown) may be formed on the top surface orthe bottom surface of the substrate base or in the substrate base. Also,a through-via (not shown) that electrically connects the top pad and thebottom pad 612 may be formed in the substrate base.

An external connection terminal 620 may be attached to a bottom surfaceof the package substrate 610. The external connection terminal 620 maybe attached to, for example, the bottom pad 612. The external connectionterminal 620 may be, for example, a solder ball or a bump. The externalconnection terminal 620 may electrically connect the semiconductorpackage 2 and an external apparatus. For example, the externalconnection terminal 620 may be disposed on the bottom surface of thepackage substrate 610, and may include an UBM layer 622 that is disposedon the bottom pad 612 and a solder ball 624 that is disposed on the UBMlayer 622. The external connection terminal 620 may further include anexternal connection pillar (not shown) disposed between the UBM layer622 and the solder ball 624, and the external connection pillar may beformed of a conductive material, for example, Cu.

For example, the UBM layer 622 may include Cr, W, Ti, Cu, Ni, al, Pd,Au, or a combination thereof. The UBM layer 622 may be a single layer ofmetal, or may have a stacked structure including a plurality of metallayers. For example, the UBM layer 622 may include a first metal layer,a second metal layer, and/or a third metal layer that are sequentiallystacked on the bottom pad 612. The first metal layer may act as anadhesive layer for stably attaching the solder ball 624 to the bottompad 612. The first metal layer may include at least one from among, forexample, Ti, Ti—W, Cr, and Al. The second metal layer may act as abarrier layer for preventing a metal material included in the bottom pad612 from diffusing into the package substrate 610. The second metallayer may include at least one from among Cu, Ni, Cr—Cu, and Ni—V. Thethird metal layer may act as a wetting layer for improving wettingproperties of the solder ball 624 or as a seed layer for forming theexternal connection pillar. The third metal layer may include at leastone from among Ni, Cu, and Al. However, the structure and the materialof the UBM layer 622 are not limited thereto.

In some embodiments, the external connection terminal 620 may have awidth and/or a height that are greater than those of the firstconnection bump 140 and the second connection bump 240. For example, thefirst and second connection bumps 140 and 240 may respectively have afirst width W1A and a second width W2A in a horizontal direction, andeach of the first width W1A and the second width W2A may range fromabout 20 μm to about 50 μm. The external connection terminal 620 mayhave a third width W3A in a horizontal direction, and the third widthW3A may be greater than 50 μm. Also, the external connection terminal620 may have a height that is equal to or greater than about 50 μm in avertical direction (e.g., a Z-direction). However, the third width W3Aand/or the height of the external connection terminal 620 are notlimited thereto.

An underfill material layer 630 may be formed between the packagesubstrate 610 and the first semiconductor chip C1. The underfillmaterial layer 630 may be disposed between the package substrate 610 andthe first semiconductor chip C1 and may surround side surfaces of thefirst connection bump 140. The underfill material layer 630 may beformed of an organic material, for example, epoxy resin. In anembodiment, the underfill material layer 630 may be a portion of asecond molding member 640 that is formed by using an MUF method.

The second molding member 640 that surrounds part or the whole of thefirst through fourth semiconductor chips C1, C2, C3, and C4 may beformed on the package substrate 610. The second molding member 640 maysurround the first molding member 150 and may not directly contact sidesurfaces of the first through fourth semiconductor chips C1, C2, C3, andC4. The second molding member 640 may be formed of, for example, an EMC.

In an embodiment, the second molding ember 640 may expose a top surfaceof the fourth semiconductor chip C4, and a heat-dissipating member (notshown) may be attached to the second molding member 640 and the fourthsemiconductor chip C4 with a thermal interface material (TIM) layer (notshown) therebetween.

The TIM layer may be formed of an insulating material or a material thatincludes an insulating material and thus may reduce or preventtransmission of electricity. The TIM layer may include, for example,epoxy resin. The TIM layer may be, for example, mineral oil, grease, gapfiller putty, phase-change gel, phase-change material pad, orparticle-filled epoxy.

The heat-dissipating member may be, for example, a heat sink, a heatspreader, a heat pipe, or a liquid-cooled cold plate.

According to the semiconductor package 2, since each of the secondthrough fourth connection bumps 240, 340, and 440 that are inter-chipsconnection bumps includes a material having desirable high-temperatureproperties, a void may be prevented from being formed during multiplehigh-temperature processes. Since the first connection bump 140 that isa substrate-chip connection bump includes a material having a lowYoung's modulus, even when warpage occurs in the package substrate 610,excellent adhesion properties may be obtained. Accordingly, thesemiconductor package 2 may have high adhesion reliability.

FIG. 9 is a cross-sectional view of a semiconductor package 2 aaccording to embodiments. In FIG. 9, the reference numerals that are thesame as the reference numerals in FIGS. 1A through 8 denote the sameelements.

Referring to FIG. 9, the semiconductor package 2 a includes a mainsemiconductor chip 700 that is attached to the package substrate 610 andthe first through fourth semiconductor chips C1, C2, C3, and C4 that aresequentially stacked on the main semiconductor chip 700.

The semiconductor package 2 a of FIG. 9 is similar to the semiconductorpackage 2 of FIG. 8 except that the main semiconductor chip 700 isadditionally formed, and thus a repeated explanation will be omitted.

The main semiconductor chip 700 may be a processor unit. The mainsemiconductor chip 700 may be, for example, a microprocessor unit (MPU)or a graphic processor unit (GPU). In an embodiment, the mainsemiconductor chip 700 may be a package, that is, a known good package(KGP) that is known to be free of defects. The main semiconductor chip700 may include a main through-electrode 720. The main through-electrode720 has a structure similar to that of each of the first through thirdthrough-electrodes 120, 220, and 320 of the first through fourthsemiconductor chips C1, C2, C3, and C4, and thus a detailed explanationthereof will not be given.

The first through third through-electrodes 120, 220, and 320 of thefirst through fourth semiconductor chips C1, C2, C3, and C4 may beelectrically connected to the main through-electrode 720 of the mainsemiconductor chip 700.

A main connection terminal 710 may be attached to a bottom surface ofthe main semiconductor chip 700. The first through fourth semiconductorchips C1, C2, C3, and C4 and the main semiconductor chip 700 may beelectrically connected to the package substrate 610 through the mainconnection terminal 710. For example, the main connection terminal 710may include a UBM layer 712 that is disposed on the bottom surface ofthe main semiconductor chip 700 and a solder ball 714 that is disposedon the UBM layer 712. The main connection terminal 710 may furtherinclude a main connection pillar (not shown) that is disposed betweenthe UBM layer 712 and the solder ball 714, and the main connectionpillar may include a conductive material, for example, Cu. In someembodiments, the main connection terminal 710 may have a width in ahorizontal direction (e.g., the X-direction) and/or a height in avertical direction (e.g., the Z-direction) that are greater than thoseof the first connection bump 140 and the second connection bump 240. Forexample, a width of the main connection terminal 710 in the horizontaldirection (e.g., the X-direction) may be equal to or greater than about50 μm and a height of the main connection terminal 710 in the verticaldirection (e.g., the Z-direction) may be equal to or greater than about50 μm. However, the width and/or the height of the main connectionterminal 710 are not limited thereto.

In an embodiment, an underfill material layer 730 that surrounds themain connection terminal 710 may be additionally formed between the mainsemiconductor chip 700 and the package substrate 610. The underfillmaterial layer 730 may be formed of an organic material, for example,epoxy resin. In an embodiment, the underfill material layer 730 may be aportion of the second molding member 640 that is formed by using an MUFmethod.

According to the semiconductor package 2 a, since each of the secondthrough fourth connection bumps 240, 340, and 440 that are inter-chipsconnection bumps includes a material having excellent high-temperatureproperties, a void may be prevented from being formed in a plurality ofhigh-temperature processes. Since the first connection bump 140 that isa substrate-chip connection bump includes a material having a lowYoung's modulus, even when warpage occurs in the package substrate 610,excellent adhesion properties may be ensured. Accordingly, thesemiconductor package 2 a may have high adhesion reliability.

FIG. 10 is a cross-sectional view of a semiconductor package 2 baccording to embodiments. In FIG. 10, the reference numerals that arethe same as the reference numerals in FIGS. 1A through 9 denote the sameelements.

Referring to FIG. 10, the semiconductor package 2 b includes a mainsemiconductor chip 700 a that is attached to the package substrate 610and the first through fourth semiconductor chips C1, C2, C3, and C4 thatare sequentially stacked on the package substrate 610.

The semiconductor package 2 b of FIG. 10 is similar to the semiconductorpackage 2 a of FIG. 9 except that the main semiconductor chip 700 a andthe sequentially stacked first through fourth semiconductor chips C1,C2, C3, and C4 are attached to different portions of the packagesubstrate 610, and thus a detailed explanation thereof will not begiven. That is, the semiconductor package 2 b of FIG. 10 includes a mainsemiconductor chip 700 a and the sequentially stacked first throughfourth semiconductor chips C1, C2, C3 and C4 spaced apart from eachother whereas the first through fourth semiconductor chips C1, C2, C3and C4 are sequentially stacked on a main semiconductor chip 700 a inFIG. 9.

FIGS. 11 through 21 are cross-sectional views for describing a method ofmanufacturing a semiconductor package according to a process orderaccording to embodiments. In one embodiment, the method may be a methodof manufacturing the semiconductor package 1 of FIGS. 1A through 1D.

Referring to FIG. 11, a first semiconductor wafer W1 is prepared. Thefirst semiconductor wafer W1 may include a plurality of the firstsemiconductor chips C1 that are divided by first scribe lanes SL1. Eachof the first semiconductor chips C1 includes the first semiconductorsubstrate 100, the first semiconductor device layer 110, and the firstthrough-electrode 120. The first semiconductor substrate 100 may have afirst top surface 102 and a first bottom surface 104 a that are oppositefrom each other. The first semiconductor device layer 110 may be formedon the first top surface 102 of the first semiconductor substrate 100.The first through-electrode 120 may pass through the first semiconductordevice layer 110 from the first top surface 102 of the firstsemiconductor substrate 100 and may extend into the first semiconductorsubstrate 100.

The first semiconductor device layer 110 may include an LSI system, aflash memory, a DRAM, an SRAM, an EEPROM, a PRAM, an MRAM, and/or anRRAM. The first semiconductor device layer 110 may include a pluralityof wiring structures for connecting a plurality of individual devices toother wiring lines formed in the first semiconductor substrate 100.

The first through-electrode 120 may extend from the first top surface102 of the first semiconductor substrate 100 into the firstsemiconductor substrate 100. At least a part of the firstthrough-electrode 120 may have a pillar shape. The firstthrough-electrode 120 may include a barrier film that is formed on asurface of the pillar shape and a buried conductive layer that is filledin the barrier film. A via insulating film may be disposed between thefirst semiconductor substrate 100 and the first through-electrode 120.The via insulating film may include an oxide film, a nitride film, acarbide film, a polymer, or a combination thereof.

The first through-electrode 120 may be formed by removing a part of thefirst semiconductor substrate 100 and making conductive materials passthrough the part of the first semiconductor substrate 100 that has beenremoved in a subsequent process. For example, the firstthrough-electrode 120 may include the barrier film and a buriedconductive layer that fills the barrier film. Alternatively, the firstthrough-electrode 120 may include, for example, the barrier film, theburied conductive layer that is filled in the barrier film, and a partof a metal wiring layer and/or a via plug.

Referring to FIG. 12, the first connection bump 140 that is electricallyconnected to the first through-electrode 120 is formed on the firstsemiconductor substrate 100. Before the first connection bump 140 isformed, the first connection pad 132 may be formed to be disposedbetween the first through-electrode 120 and the first connection bump140.

The first connection bump 140 may include the first pillar structure 142and the first solder layer 148. In order to form the first connectionbump 140, a mask pattern (not shown) having an opening (not shown)through which a portion of the first connection pad 132 is exposed maybe formed on the first semiconductor device layer 110. Next, the firstpillar structure 142 and the first solder layer 148 may be sequentiallyformed on the portion of the first connection pad 132 that is exposedthrough the mask pattern. In an embodiment, the first pillar structure142 and the first solder layer 148 may be formed by performing anelectroplating process.

In some embodiments, the first pillar structure 142 may include thefirst pillar layer 144 (see FIG. 1C) and the diffusion barrier layer 146(see FIG. 1C) that are sequentially formed on the first connection pad132. In other embodiments, the first pillar structure 142 a (see FIG. 2)may include the first pillar layer 144 (see FIG. 2), the diffusionbarrier layer 146 (see FIG. 2), and the adhesive layer 147 (see FIG. 2)that are sequentially formed on the first connection pad 132. In otherembodiments, an additional etching process for removing side walls ofthe first pillar layer 144 b (see FIG. 3) and the adhesive layer 147 b(see FIG. 3) by a predetermined width may be further performed using anetching condition in which the diffusion barrier layer 146 b (see FIG.3) may be hardly etched.

Next, the first solder layer 148 having a convex shape may be formed byremoving the mask pattern and reflowing the first solder layer 148 byusing thermal treatment.

Referring to FIG. 13, the first semiconductor wafer W1 including thefirst connection bump 140 is attached to a first carrier substrate 10.The first carrier substrate 10 may include a first support substrate 12and a first adhesive material layer 14. The first semiconductor wafer W1may be attached to the first carrier substrate 10 so that the firstconnection bump 140 faces the first carrier substrate 10. The firstconnection bump 140 may be surrounded by the first adhesive materiallayer 14. A portion of the first top surface 102 of the firstsemiconductor substrate 100 that is exposed through the first connectionbump 140 may contact the first adhesive material layer 14.

Referring to FIG. 14, the first through-electrode 120 is exposed byremoving a portion of the first semiconductor substrate 100. The firstthrough-electrode 120 may be exposed on the first bottom surface 104 ofthe first semiconductor substrate 100. Since the first through-electrode120 is exposed on the first bottom surface 104 of the firstsemiconductor substrate 100, the first through-electrode 120 may passthrough the first semiconductor substrate 100. Alternatively, a portionof the first semiconductor substrate 100 may be removed so that thefirst through-electrode 120 protrudes beyond the first bottom surface104.

In order to expose the first through-electrode 120, a portion of thefirst semiconductor substrate 100 may be removed by using a chemicalmechanical polishing (CMP) process, an etch-back process, or acombination thereof.

Referring to FIG. 15, the first rear protective layer 136 is formed tocover an exposed surface of the first semiconductor wafer W1. That is,the first rear protective layer 136 is formed to cover the first bottomsurface 104 of the first semiconductor substrate 100. The first rearprotective layer 136 may be formed by using, for example, a spin coatingprocess or a spray process. The first rear protective layer 136 may beformed from, for example, an insulating polymer. In order to form thefirst rear protective layer 136, an insulating polymer film may beformed that covers the first bottom surface 104 of the firstsemiconductor substrate 100 and the first through-electrode 120, andthen a part of the insulating polymer film may be removed by using anetch-back process to expose a portion of the first through-electrode120.

Referring to FIG. 16, the first upper connection pad 134 that iselectrically connected to the portion of the first through-electrode 120that is exposed through the first rear protective layer 136 is formed.Alternatively, the first upper connection pad 134 may not be formed.

Referring to FIG. 17, the second semiconductor chip C2 is prepared. Thesecond semiconductor chip C2 may be prepared by processing a secondsemiconductor wafer (not shown) and then separating the secondsemiconductor wafer, like in the first semiconductor wafer W1 of FIGS.11 through 14.

The second semiconductor wafer may be a semiconductor wafer thatincludes the same individual devices, which are formed by using the sameprocess as that in the first semiconductor wafer W1, as those of thefirst semiconductor wafer W1. That is, a plurality of the secondsemiconductor chips C2 that are connected together may be attached asthe second semiconductor wafer to a second carrier substrate 20 and thenmay be cut separately into the second semiconductor chips C2. Each ofthe second semiconductor chip C2 includes the second semiconductorsubstrate 200, the second semiconductor device layer 210, and the secondthrough-electrode 220. The second semiconductor substrate 200 may have asecond top surface 202 and a second bottom surface 204 that are oppositefrom each other. The second through-electrode 220 may pass through thesecond semiconductor substrate 200.

The second semiconductor chip C2 may be a semiconductor chip thatincludes the same individual devices as the individual devices of thefirst semiconductor chip C1. Alternatively, the second semiconductorchip C2 may be a semiconductor chip that includes individual devicesthat are different from the individual devices of the firstsemiconductor chip C1.

The second semiconductor chip C2 may include the second connection bump240 having a structure that is different from that of the firstconnection bump 140. The second connection bump 240 may include thesecond pillar structure 242 and the second solder layer 248. The secondpillar structure 242 may include a material having betterhigh-temperature properties than a material included in the first pillarstructure 142. For example, the second pillar structure 242 may includeNi or a Ni alloy. The second connection bump 240 has already beenexplained in detail regarding FIG. 1D.

Referring to FIG. 18, the first insulating layer 152 may be attached tothe first semiconductor wafer W1. The first insulating layer 152 may bedisposed on the plurality of first semiconductor chips C1 to contact thefirst rear protective layer 136 and the first upper connection pad 134.The first insulating layer 152 may be formed from an insulating polymer.

Referring to FIG. 19, the plurality of second semiconductor chips C2 areseparated from the second carrier substrate 20 of FIG. 17 and arestacked on the first semiconductor wafer W1 of FIG. 18. The plurality ofsecond semiconductor chips C2 may be stacked on the first semiconductorwafer W1 to respectively correspond to the plurality of firstsemiconductor chips C1 of the first semiconductor wafer W1. That is, theplurality of second semiconductor chips C2 may be stacked on theplurality of first semiconductor chips C1 to respectively correspond tothe plurality of first semiconductor chips C1.

Each of the second semiconductor chip C2 may be stacked on the firstsemiconductor chip C1 to electrically connect the firstthrough-electrode 120 and the second through-electrode 220. In order toelectrically connect the first through-electrode 120 and the secondthrough-electrode 220, the second semiconductor chip C2 may be stackedon the first semiconductor chip C1 so that the second connection bump240 of the second semiconductor chip C2 contacts the first upperconnection pad 134. When the first upper connection pad 134 is notformed, the second connection bump 240 may contact the firstthrough-electrode 120. The first insulating layer 152 may be disposedbetween the first semiconductor chip C1 and the second semiconductorchip C2 to surround the first upper connection pad 134 and the secondconnection bump 240.

After the second semiconductor chip C2 is stacked on the firstsemiconductor chip C1, an adhesive force between the second connectionbump 240 and the first upper connection pad 134 or between the secondconnection bump 240 and the first through-electrode 120 may be increasedby performing a reflow process or a thermal compression process, and acontact resistance may be reduced.

Next, the second insulating layer 154 is disposed on the plurality ofsecond semiconductor chips C2 and the plurality of third semiconductorchips C3 are stacked on the first semiconductor wafer W1 to respectivelycorrespond to the plurality of second semiconductor chips C2 byrepeatedly performing processes of FIGS. 17 through 19. The thirdinsulating layer 156 is disposed on the plurality of third semiconductorchips C3 and the plurality of fourth semiconductor chips C4 are stackedon the first semiconductor wafer W1 to respectively correspond to theplurality of third semiconductor chips C3. The third and fourthsemiconductor chips C3 and C4 may be semiconductor chips including thesame individual devices as the individual devices of the firstsemiconductor chip C1. Alternatively, the third and fourthssemiconductor chips C3 and C4 may be semiconductor chips includingindividual devices that are different from the individual devices of thefirst semiconductor chip C1.

A reflow process or a thermal compression process may be performed afterthe third semiconductor chips C3 are stacked on the second semiconductorchips C2, or a reflow process or a thermal compression process may beperformed after the fourth semiconductor chips C4 are stacked on thethird semiconductor chips C3.

Although a stacked structure in which the second through fourthsemiconductor chips C2, C3, and C4 are stacked on the firstsemiconductor wafer W1 in the vertical direction is illustrated in FIG.19, the number of semiconductor chips stacked on the first semiconductorwafer W1 is not limited thereto.

In some embodiments, a first underfill layer (not shown), instead of thefirst insulating layer 152, may be formed between the firstsemiconductor chip C1 and the second semiconductor chip C2. The firstunderfill layer may be formed from epoxy resin by using, for example, acapillary underfill method. The first underfill layer may be combinedwith a filler, and the filler may be formed from, for example, silica.

Referring to FIG. 20, the first mold layer 162 that covers the secondthrough fourth semiconductor chips C2, C3, and C4 is formed on the firstsemiconductor wafer W1. The first mold layer 162 may be formed to coverside surfaces of the second and third semiconductor chips C2 and C3 anda side surface and a top surface of the fourth semiconductor chip C4.Since the first through third insulating layers 152, 154, and 156 aredisposed between the first through fourth semiconductor chips C1, C2,C3, and C4, the first mold layer 162 may surround side surfaces of thefirst through third insulating layers 152, 154, and 156. In someembodiments, the first mold layer 162 may be formed from an EMC.

Referring to FIG. 21, the first semiconductor wafer W1 may be cut alongthe first scribe lanes SL1 (see FIG. 20) into the semiconductor packages1 each including the first through fourth semiconductor chips C1, C2,C3, and C4.

Each semiconductor package 1 may include the first semiconductor chip C1including the first through-electrode 120, the second semiconductor chipC2 that is stacked on the first semiconductor chip C1 with the firstinsulating layer 152 therebetween and includes the secondthrough-electrode 220, the third semiconductor chip C3 that is stackedon the second semiconductor chip C2 with the second insulating layer 154therebetween and includes the third through-electrode 320, and thefourth semiconductor chip C4 that is stacked on the third semiconductorchip C3 with the third insulating layer 156 therebetween.

A horizontal cross-sectional area of each of the second through fourthsemiconductor chips C2, C3, and C4 may be smaller than a horizontalcross-sectional area of the first semiconductor chip C1. The first moldlayer 162 may be formed on a portion of the first semiconductor chip C1to surround the side surfaces of the second through fourth semiconductorchips C2, C3, and C4. Since the first mold layer 162 is formed on aportion of the first semiconductor chip C1 to surround the side surfacesof the second through fourths semiconductor chips C2, C3, and C4, thefirst connection bump 140 that is disposed on a bottom surface of thefirst semiconductor chip C1 may not contact the first mold layer 162.

According to the method of manufacturing the semiconductor package 1,the second through fourth semiconductor chips C2, C3, and C4 aresequentially stacked on the first semiconductor wafer W1, and a processof thermally compressing or reflowing the second through fourthsemiconductor chips C2, C3, and C4 is repeatedly performed a pluralityof times. Accordingly, a plurality of high-temperature processes may beperformed on the second through fourth connection bumps 240, 340, and440 that are disposed between the first through fourth semiconductorchips C1, C2, C3, and C4.

In general, when a semiconductor package is exposed to ahigh-temperature environment, an intermetallic compound may be formedbetween a solder layer of a connection bump and a connection pad orbetween a pillar layer of the connection bump and the solder layer, andan excessive amount of intermetallic compounds may be formed in aplurality of high-temperature processes. For example, when an excessiveamount of intermetallic compounds are formed, the solder layer may beconsumed and a void may be formed in the solder layer. Also, since theintermetallic compounds have a high brittleness, a crack may be easilyformed in the intermetallic compounds due to a mechanical impact fromthe outside of the semiconductor package. Accordingly, when an excessiveamount of intermetallic compounds is formed, the reliability of thesemiconductor package may be reduced.

However, according to the semiconductor package 1, since each of thesecond through fourth pillar structures 242, 342, and 442 of the secondthrough fourth connection bumps 240, 340, and 440 that are inter-chipsconnection bumps includes a material having relatively goodhigh-temperature properties, even when a plurality of high-temperatureprocesses are performed, an excessive amount of intermetallic compoundsmay be prevented from being formed.

Also, the first pillar structure 142 of the first connection bump 140that is a substrate-chip connection bump may be mounted on an underlyingsubstrate (not shown) or an interposer (not shown). Warpage may easilyoccur in the underlying substrate or the interposer in a reflow processor a molding process. The first pillar structure 142 may include amaterial having a Young's modulus that is lower than that of a materialincluded in the second pillar structure 242. Accordingly, even whenwarpage occurs in the underlying substrate or the interposer, since thefirst pillar structure 142 has a relatively large elasticity, a crackmay be prevented from being formed in an interface between the firstpillar layer 144 and the first solder layer 148.

In conclusion, since each of the second through fourth connection bumps240, 340, and 440 that are inter-chips connection bumps includes amaterial having excellent high-temperature properties, a void may beprevented from being formed in a plurality of high-temperatureprocesses. Since the first connection bump 140 that is a substrate-chipconnection bump includes a material having a low Young's modulus, evenwhen warpage occurs in an underlying substrate or an interposer,excellent adhesion properties may be ensured. Accordingly, thesemiconductor package 1 may have high adhesion reliability.

While the inventive concept has been particularly shown and describedregarding embodiments thereof, it will be understood that variouschanges in form and details may be made therein without departing fromthe scope of the following claims.

What is claimed is:
 1. A semiconductor package comprising: a firstsemiconductor chip that includes a first through-electrode; a pluralityof second semiconductor chips stacked on a top surface of the firstsemiconductor chip, at least one of the plurality of secondsemiconductor chips including a second through-electrode; a plurality offirst connection bumps attached to a bottom surface of the firstsemiconductor chip, each of the plurality of first connection bumpscomprising a first pillar structure and a first solder layer; and aplurality of second connection bumps located between the firstsemiconductor chip and a lowermost second semiconductor chip and betweenadjacent two second semiconductor chips among the plurality of secondsemiconductor chips, each of the plurality of second connection bumpscomprising a second pillar structure and a second solder layer, whereinthe first pillar structure comprises a first pillar layer and adiffusion barrier layer sequentially stacked on the bottom surface ofthe first semiconductor chip, the first pillar layer comprises amaterial that is different from a material of the second pillarstructure.
 2. The semiconductor package of claim 1, wherein the firstpillar layer located on the bottom surface of the first semiconductorchip; and the diffusion barrier layer located on the first pillar layerfarther from the bottom surface of the first semiconductor chip than thefirst pillar layer is located from the bottom surface of the firstsemiconductor chip.
 3. The semiconductor package of claim 2, wherein thefirst pillar layer of the first pillar structure comprises a materialhaving a Young's modulus that is lower than a Young's modulus of amaterial included in the second pillar structure.
 4. The semiconductorpackage of claim 2, wherein the first pillar structure comprises copper(Cu) and the second pillar structure comprises nickel (Ni).
 5. Thesemiconductor package of claim 2, wherein the first pillar layer of thefirst pillar structure comprises Cu and the diffusion barrier layercomprises Ni.
 6. The semiconductor package of claim 2, wherein the firstpillar structure further comprises an adhesive layer formed on thediffusion barrier layer and comprises Cu.
 7. The semiconductor packageof claim 1, wherein the first through-electrode is connected to at leastone of the plurality of first connection bumps or the plurality ofsecond connection bumps.
 8. The semiconductor package of claim 1,further comprising a first molding member that surrounds side surfacesof the plurality of second semiconductor chips and the plurality ofsecond connection bumps and does not contact the bottom surface of thefirst semiconductor chip or the plurality of first connection bumps. 9.The semiconductor package of claim 1, wherein a first height of thefirst pillar structure in a first direction that is perpendicular to thetop surface of the first semiconductor chip is greater than a secondheight of the second pillar structure in the first direction.
 10. Thesemiconductor package of claim 1, wherein the second solder layercomprises a material having a melting point higher than a melting pointof the first solder layer.
 11. The semiconductor package of claim 1,further comprising: a substrate facing the bottom surface of the firstsemiconductor chip and electrically connected to the first semiconductorchip through the plurality of first connection bumps; and an externalconnection terminal located on a bottom surface of the substrateopposite to a top surface of the substrate that faces the firstsemiconductor chip, wherein a width of one of the plurality of firstconnection bumps in a second direction that is parallel to the topsurface of the first semiconductor chip is smaller than a width of theexternal connection terminal in the second direction.
 12. Thesemiconductor package of claim 11, wherein the substrate is aninterposer or a printed circuit board (PCB), wherein the width of theexternal connection terminal in the second direction is greater than 50μm.
 13. The semiconductor package of claim 11, further comprising: afirst molding member that surrounds side surfaces of the plurality ofsecond semiconductor chips and the plurality of second connection bumpsand does not contact the bottom surface of the first semiconductor chipor the plurality of first connection bumps; and a second molding memberlocated between the substrate and the bottom surface of the firstsemiconductor chip and surrounds the plurality of first connectionbumps.
 14. A semiconductor package comprising: a substrate; a firstsemiconductor chip mounted on a top surface of the substrate andcomprising a through-electrode provided therein; a second semiconductorchip mounted on a top surface of the first semiconductor chip andcomprising a through-electrode provided therein; a third semiconductorchip mounted on a top surface of the second semiconductor chip; aplurality of first connection bumps located between the firstsemiconductor chip and the substrate, each of the plurality of firstconnection bumps comprising a first pillar structure and a first solderlayer; and a plurality of second connection bumps located between thefirst semiconductor chip and the second semiconductor chip and betweenthe second semiconductor chip and the third semiconductor chip, each ofthe plurality of second connection bumps comprising a second pillarstructure and a second solder layer, wherein the first pillar structurecomprises a material that is different from a material of the secondpillar structure.
 15. The semiconductor package of claim 14, wherein thefirst pillar structure comprises a material having a Young's moduluslower than a Young's modulus of a material included in the second pillarstructure.
 16. The semiconductor package of claim 14, further comprisingan external connection terminal located on a bottom surface of thesubstrate and comprising an under-bump metal (UBM) layer and a solderball, which are sequentially located on the bottom surface of thesubstrate.
 17. The semiconductor package of claim 14, wherein the firstpillar structure comprises: a first pillar layer located on a bottomsurface of the first semiconductor chip; and a diffusion barrier layerlocated on the first pillar layer farther from the bottom surface of thefirst semiconductor chip than the first pillar layer is located from thebottom surface of the first semiconductor chip, the diffusion barrierlayer contacting the first solder layer.
 18. A semiconductor package,comprising: a first semiconductor chip; a plurality of first connectionbumps attached to a bottom surface of the first semiconductor chip, eachof the plurality of first connection bumps comprising a first pillarstructure and a first solder layer, the first pillar structurecomprising a first material having a first Young's modulus; a pluralityof second semiconductor chips stacked on a top surface of the firstsemiconductor chip; and a plurality of second connection bumps locatedbetween the first semiconductor chip and a lowermost secondsemiconductor chip and between adjacent two second semiconductor chipsamong the plurality of second semiconductor chips, each of the pluralityof second connection bumps comprising a second pillar structure and asecond solder layer, the second pillar structure comprising a secondmaterial having a second Young's modulus, the second Young's modulusbeing greater than the first Young's modulus.
 19. The semiconductorpackage of claim 18, wherein a first height of the first pillarstructure in a first direction that is perpendicular to the top surfaceof the first semiconductor chip is greater than a second height of thesecond pillar structure in the first direction.
 20. The semiconductorpackage of claim 18, wherein the second solder layer comprises amaterial having a melting point that is higher than a melting point ofthe first solder layer.